Centrifugal casting apparatus



Jam 1963 A. WITTMOSER ETAL 3,

CENTRIFUGAL CASTING APPARATUS Filed June 22, 1959 United tates Patent 3,h74,l30 Patented Jan. 22, 1963:

3,074,130 CENTRH UGAL CASTING APEARATUS Adaibert Wittmoser, Gelsenkirchen-llner, and Werner Trojahn, Gelsenkirchen, Germany, assignors to Rheinstahl Eisenwerke Geisenkirchen A.G., Gelsenkirchen,

Germany Filed June 22, 1959, Ser. No. 821,841 2 Claims. (Cl. 22-65) The present invention relates to apparatus for the manufacture of tubular bodies by the centrifugal casting process, and more particularly to a system for inserting the core into and for withdrawing the core from the mold of a centrifugal casting machine.

Known centrifugal casting machines, for example those equipped with fluid-cooled chill molds or coquilles for the manufacture of flanged pipes, utilize smooth or threaded cores provided with preferably metallic core rings usually mounted in the extended flange end of the mold. Proper axial positioning of the core is brought about by the provision of Wedge-shaped members which may be forced through suitable apertures in the flange end of the mold and which must be removed before the corecan be separated from the mold.

The insertion and often also the withdrawal of cores and core rings may be brought about by a spindle which is coaxially insertable into the core and is axially movable with respect to the centrifugal casting apparatus. When a core is properly inserted into the mold, the spindle is withdrawn for the duration of the actual casting operation to be reinserted into the core when the latter is to be removed from the hardened casting. It is also known to swingably mount the spindle on a horizontal or vertical pin in order to provide room for subsequent drawing of the pipe as well as to permit insertion of the ejecting apparatus for the finished product.

The just described conventional procedure of inserting and withdrawing a core in centrifugalcasting apparatus is rather lengthy since it requires, in that order, insertion of a core, removal of the core inserting means, wedging or locking of the core with respect to the mold, loosening of the wedges upon completion of a casting operation, introduction of core withdrawing means, and actual withdrawal of the core. This has led to numerous proposals for simplifying the known procedures, for example, by utilizing oneor multi-piece cores which may be rotatably held by the inserting and withdrawing means therefor while a casting operation takes place. One known arrangement of such character utilizes an axially movable threaded spindle which, when in operative position, is coaxial with the mold and is connected to a housing pivotably attached to the front end of the centrifugal casting machine. The spindle is also connected witha hand wheel or the like for axial displacements toward and away from the mold. The disadvantage of such construction is in that the pivotable housing and the spindle carried thereby occupy too much space and prevent the mounting of the actual tube drawing means at a convenient, i.e. rather short, distance from the open end of'tbe mold. Consequently, the drawing means must cover comparatively long distances when moved into and out of operative position.

An important object of the present invention is to provide a centrifugal casting machine equipped with a simple and conveniently operable core inserting and withugal casting machines.

A further object of the invention is to provide a core inserting and withdrawing system which may simultaneously control two or more cores.

A still further object of the invention is to provide a centrifugal casting machine equipped with novel core supporting, inserting and withdrawing means which may be utilized for casting of smooth-walled as well as of threaded tubular bodies.

A concomitant object of the invention is to provide a centrifugal casting machine equipped with core supporting and moving means of the above outlined type which is constructed with a view to shorten the intervals between successive casting operations and which, when constructed for use with more than one core, allows for cooling of one or more core supporting means while another core supporting means is in actual use.

With the above objects in view, the invention consists essentially in the provision of a centrifugal casting machine which comprises a rotatable mold, e.g. a chill, a spindle mounted in parallelism with the latters axis, means for rotating and axially displacing the spindle, and at least one lever connected with the spindle and adapted to support a holder or carrier for a core. The holder or holders may be moved by the spindle toward and away from the open end of the mold to either introduce or withdraw the respective core, as well as in an are about the spindle to move the respective core into axial alignment with or away from the open end of the mold. In this manner, an axially and angularly movable spindle may control all necessary movements of the core or cores into the position for casting as well as into the position in which the tube drawing and ejecting means may be introduced into the mold.

According to another feature of the invention, each aforementioned lever may support a braking device operatively connected with the respective core to arrest the latters angular movements when the core is withdrawn from the mold, and more particularly from the casting therein. Also, the braking means for the core may be operatively connected with the means, e.g. a cylinder and piston assembly, for axially moving the spindle in order to avoid damage to the casting especially if the casting is internally threaded.

An important advantage attendantto the provision of two or more core-supporting levers on the spindle is in that the core holders may be cooled between successive casting operations, and in that the operation is rendered even moreeconomical since angular displacements necessary for moving one core into operative position may simultaneously cause at least partial advance of another core into idle position or vice versa.

The novel features which are considered as character'- istic for the invention are set forthin particular in the appended claims. The invention. itself, however, both as to its construction and its method of operation, together with additional objects'and advantages thereof, will be best understood from the following. description of a specific embodiment when read in connection with the accompanying drawing, in which:

FIG. 1 is schematic side elevational view of a centrifugal casting machine embodying the invention, a portion of the mold-supporting casing being broken away; and

FIG. 2 is an end view of the machine as seen from the left-hand end of FIG. 1.

Referring now in greater detail to the drawing, there is shown a centrifugal casting machine M which comprises a casing or shell 2 rotatably receiving the mold 1, e.g. a coquille or chill, and supporting thereon a number of aligned bearings 3 for a spindle 4. The latter is axially parallel with the mold 1 and may be disposed above (as shown) or laterally of the casing 2. At its one extremity extending beyond the exposed or open end of mold 1, spindle 4 is rigidly connected with a lever 5 whose free end, in turn, is connected with a carrier or holder 6 for a core 7. Core 7 is rotatable with respect to its holder 6 in suitable ball bearings (not shown). The hollow shaft 6a of holder 6 supports a friction disc or brake pulley 8 and coaxially receives a second shaft 8a which connects pulley 8 for rotation with core 7. Lever 5 further supports a cylinder and piston assembly whose rod 10a is connected with one end of a hand brake 9. The other end of member 9 is connected with a pin 5a anchored in lever 5. The shafts 6a, 8a may be swung by spindle 4 in an arc so that their axes intersect the axis of mold 1 in a given angular position of the spindle.

The second or rear end of spindle 4 is connected with the plunger 11a of a cylinder and piston assembly 11 which latter is mounted on casing 2. Spindle 4 is angularly displaceable in its bearings 3 by an arm 12 which is articulately connected to the rod 13a of a further cylinder and piston assembly 13 by a pair of links 12a. The end of arm 12 may be formed as a wedge to enter a complementary groove or recess in the spindle 4.

The centrifugal apparatus M operates as follows:

A core 7 is first attached to holder 6 and fixed for rotation with the end of shaft 8:: while the lever 5 is in the phantom-line position 5 shown in FIG. 2. Assembly 13, arm 12 and spindle 4 then return the lever 5 back into its full-line position to move the core- 7 in front of and into axial alignment with the rotating mold or chill 1. The means for rotating the mold are not shown in the drawing. Piston 11a of the assembly 11 then axially displaces the spindle 4 in a direction to right (FIG. 1) whereby the core 7 is caused to enter into the open end of the chill or mold 1 to be retained in the phantom-line position 7' during the next-following casting operation.

Upon introduction and setting of molten material in the space between parts 1 and 7, and preferably before the end portion of the tube is cast, cylinder assembly 10 is caused to draw the brake band 9 tight about its drum or pulley 8 in order to arrest the angular movement of core 7. The latter is simultaneously withdrawn from the bore of the casting by the arm 5, spindle 4 and the piston 11a of assembly 11 to return into its full-line position of FIG. 1. In the next step, the spindle 4 is angularly displaced by arm 12 and assembly 13 to move the lever 5 into its phantom-line position 5'. The access to the exposed end of mold 1 and to the casting therein is then unobstructed, and the customary drawing machine may be introduced into the casing 2.

Of course, when an internally threaded casting is produced, the braking of angular movements and the axial movements of core 7 must be synchronized so as to avoid damage to the threads formed in the interior of the product. For example, a suitable connection may be provided between assemblies 10 and 11 to bring about axial displacements of shaft 4 in response to increasing braking action of band 9.

. The spindle 4 may be connected with two or more radial levers similar to member 5 each of which may support a separate core 7. This results in the additional advantage that the cores may be used alternately in a given sequence, thus allowing for cooling of all core holders with the exception of that supporting the core which is momentarily in actual use. Also, while a selected holder or carrier 6 and the core 7 connected therewith are in actual use, the cores of all other holders may be interchanged and fully prepared for the next casting operation or operations, depending upon the number of levers connected with the spindle 4. As already mentioned hereinabove, such arrangement renders the operation of the improved apparatus even more economical since the levers 5 may be so positioned with respect to each other that one core 7 is moved into axial alignment with the mold 1 while another core is simultaneously moved at least partially into the position corresponding to the phantom-line position 5' of the lever 5 shown in FIG. 2. For example, it can be assumed that the phantom lines 5' shown in FIG. 2 represent a second lever identical with member 5, and that the stroke of the piston forming part of assembly 13 is sufi'icient to move the lever 5 to the right of its full-line position sufficiently to place the core connected with the assumed lever 5' into axial alignment with mold 1. It will be readily understood that the parts 12, 12a, 13, 13a whose purpose is to angularly displace the spindle 4 then require certain modifications.

The cylinders of assemblies 10, 11, 13 may utilize a liquid or gaseous pressure medium.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of metal casting apparatus differing from the type described above.

While the invention has been illustrated and described as embodied in an apparatus for casting tubes and the like, it is not intended to be limited to the details shown since various modifications and structural changes may be made Without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic and specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In a centrifugal casting machine, in combination: a mold having an axis; a spindle axially parallel with said mold; means for axially and angularly displacing said spindle; a lever rigidly connected to said spindle; core supporting means connected to said lever and movable by the spindle in an are passing through the axis of said mold; a core carried by said supporting means and rotatable relative thereto; and brake means operatively connected with said core for arresting the latter, said brake means comprising a pulley connected for rotation with said core, a belt on said pulley, and a cylinder and piston assembly carried by said lever and connected with said belt for tensioning same, said core being movable into and out of axial alignment with, as Well as toward and away from, said mold upon angular and axial displacements, respectively, of said spindle.

2. In a centrifugal casting machine, in combination: a casing; a mold rotatably installed in said casing,- said mold having an axis and an open end; bearings carried by said casing; a spindle rotatably received in said bearings and axially parallel with said mold, said spindle having a first end extending beyond the open end of said mold and a second end; a first cylinder and piston assembly supported by said casing and connected with the second end of said spindle for axialiy displacing same; a second cylinder and piston assembly carried by said casing and operatively connected with said spindle for angularly displacing same; a lever radially extending from and connected with the first end of said spindle; a core holder connected with said lever at a point distant from said spindle, said holder comprising a hollow shaft connected to said lever; and brake means carried by said 5 lever and comprising a second shaft received in the hollow shaft of and connectable to a core supported by said holder, a brake pulley connected for rotation with said second shaft, a brake band on said pulley, and a cylinder and piston assembly operatively connected with said band for tensioning same so as to arrest rotation of said second shaft and of the core connected thereto, said holder being movable by the spindle in an arc passing through the axis of said mold whereby a core connected with said holder is movable into and out of axial alignment with, 15

as well as toward and away from the open end of, said mold when the spindle is angularly and axially displaced by said second and first cylinder and piston assemblies, respectively.

References Cited in the file of this patent UNITED STATES PATENTS 550,089 Armand et al. Nov. 19, 1895 1,567,488 Buchartz Dec. 29, 1925 2,479,610 Frei Aug. 23, 1949 2,613,410 Johnston Oct. 14, 1952 2,849,769 Lesater Sept. 2, 1958 2,857,638 Ribeiro Oct. 28, 1958 

1. IN A CENTRIFUGAL CASTING MACHINE, IN COMBINATION: A MOLD HAVING AN AXIS; A SPINDLE AXIALLY PARALLEL WITH SAID MOLD; MEANS FOR AXIALLY AND ANGULARLY DISPLACING SAID SPINDLE; A LEVER RIGIDLY CONNECTED TO SAID SPINDLE; CORE SUPPORTING MEANS CONNECTED TO SAID LEVER AND MOVABLE BY THE SPINDLE IN AN ARC PASSING THROUGH THE AXIS OF SAID MOLD; A CORE CARRIED BY SAID SUPPORTING MEANS AND ROTATABLE RELATIVE THERETO; AND BRAKE MEANS OPERATIVELY CONNECTED WITH SAID CORE FOR ARRESTING THE LATTER, SAID BRAKE MEANS COMPRISING A PULLEY CONNECTED FOR ROTATION 